Cream of Tartar in Natural Dyeing: What It Does, When to Use It, Dosage, and What to Pair It With

Cream of tartar (potassium bitartrate) is a traditional natural dyeing assistant used together with alum—especially when working with wool and silk. It helps keep the mordant bath gently acidic, supports more even uptake, and is often used to brighten/clarify certain shades (especially some reds).

If you’re here because you want to buy cream of tartar and you don’t want any guesswork: this guide shows you exactly when you need it, how much to use, and what to pair it with for reliable results.

Buy Cream of Tartar here 

1) What it is (in practical terms)

Cream of tartar is not a dye. It’s an assistant that supports your process—mainly on protein fibres (wool & silk). It is seldom used with cellulose fibres (cotton/linen) compared to wool/silk workflows.

2) The core pairing: Cream of tartar + Alum

Most dyers use cream of tartar because they are using alum. Think of alum as the main mordant and cream of tartar as the helper that supports more even, cleaner results on wool/silk.

Get Alum here:   Aluminium Potassium Sulphate (Alum)

3) Dosage (no fluff)

A reliable starting point for wool & silk is:

• Alum: 10–15% WOF
• Cream of tartar: 5–6% WOF

(WOF = Weight Of Fibre)

For a full step-by-step mordanting guide (wool & silk):

/blogs/news/how-to-mordant-protein-fibres-wool-silk

4) Quick method (wool & silk)

1. Scour first (clean fibre = even results).
2. Dissolve alum fully in hot water.
3. Add cream of tartar and stir until dissolved.
4. Add wetted fibre, heat gently (avoid boiling), then allow the fibre to cool in the bath for more even uptake.

5) When you’ll actually notice the difference

Cream of tartar is most useful when you care about clean, clear shades and even results on wool/silk—especially for many reds and warm tones.

One classic pairing is madder:

• Mordant with alum + cream of tartar
• Then dye with madder

Madder Root Powder

Madder Extract

6) What about cotton & linen?

Here’s the honest version: for cotton/linen, cream of tartar is usually not the main lever. You’ll often get more improvement from the correct cellulose workflow (commonly tannin before alum), proper scouring, and good process control.

If you want dye-ready base materials, browse:

Undyed materials for natural dyeing

7) FAQ

Do I need cream of tartar for every dye?

No. It’s optional and most relevant for alum workflows on wool/silk.

Can I use it without alum?

It’s an assistant, not a stand-alone mordant. It’s typically used alongside alum.

Will it change my colour dramatically?

Sometimes you’ll notice clearer/brighter shades, especially in certain reds and warm tones—but results vary with fibre type, water chemistry, dye material, and method.

Is there a “perfect” recipe?

There are strong starting points (above), but natural dyeing results always vary. Use the recipe as a baseline, then adjust based on your fibre, water, and dye.

8) Final note

Cream of tartar is a small addition that can make a real difference when used in the right place—mainly alum mordanting on wool and silk. Treat it like a precision tool: use it intentionally, not automatically.